<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <title>CSS漩涡背景效果</title>
    <link rel="stylesheet" href="style.css" />
  </head>
  <body>
    <div class="bg">
      <span style="--i: 0"></span>
      <span style="--i: 1"></span>
      <span style="--i: 2"></span>
      <span style="--i: 3"></span>
      <span style="--i: 4"></span>
      <span style="--i: 5"></span>
      <span style="--i: 6"></span>
      <span style="--i: 7"></span>
      <span style="--i: 8"></span>
      <span style="--i: 9"></span>
      <span style="--i: 10"></span>
      <span style="--i: 11"></span>
    </div>
  </body>
</html>
